JP5604054B2 - Method for manufacturing optical lens or optical waveguide or optical fiber core - Google Patents

Description

The present invention relates to a method for manufacturing an optical lens or a core of an optical waveguide or an optical fiber .

  An optical component, for example, an optical lens is formed in a predetermined three-dimensional shape so as to exhibit performance such as light focusing and divergence. Optical recording media such as CD (Compact Disc), DVD (Digital Versatile Disc), and BD (Blu-rey Disc) have a multilayer structure, and the surface (recording surface) of the recording layer has a three-dimensional shape such as irregularities. Is formed. Note that a metal layer is formed on the uneven recording surface of the recording layer of the optical recording medium, and a resin layer is formed on the surface of the metal layer.

  For three-dimensional optical parts such as the above optical lenses and optical recording media, as a manufacturing method for high density, high heat resistance, or low-cost production, a resin is used as a forming material, and a molding die is stamped on the resin. Thus, a method of manufacturing a three-dimensional optical component having the predetermined shape and the uneven shape has been studied.

  Such three-dimensional optical component manufacturing methods are roughly classified into two types from the viewpoint of dimensional stability. One is a method in which a molding die is press-bonded to a heat-melted thermoplastic resin, and then the thermoplastic resin is cooled to obtain a three-dimensional optical component made of a cured product of the thermoplastic resin. The other is that the mold is pressed into a liquid or paste-like UV curable resin, and then the UV curable resin is exposed by irradiating the UV through the mold and the photosensitive resin. This is a method for obtaining a three-dimensional optical component made of a cured product.

  The two types of manufacturing methods are generally selected based on the required heat-resistant temperature. That is, in fields where heat resistance is not required, transparent thermoplastic resins such as PMMA (polymethyl methacrylate), polycarbonate, polynorbornene are used, and in fields where heat resistance such as solder reflow and autoclave is required, An ultraviolet curable resin containing an epoxy resin as a main resin component is used.

  As an example thereof, a method of manufacturing the above-described three-dimensional optical component having a predetermined shape and an uneven shape using the ultraviolet curable resin has been proposed (for example, see Patent Documents 1 and 2). In this manufacturing method, an ultraviolet curable resin is supplied onto a substrate, the ultraviolet curable resin is embossed with a molding die, and the ultraviolet curable resin thus embossed is irradiated with ultraviolet rays in that state. In this method, the ultraviolet curable resin between the substrate and the mold surface of the mold is exposed to produce a three-dimensional optical component made of a cured product of the ultraviolet curable resin.

JP 2002-355826 A JP-A-9-115191

  By the way, in the method of curing an ultraviolet curable resin by exposure as in the prior art described above, in general, in order to increase the curability of the ultraviolet curable resin and the sensitivity to ultraviolet rays, a photoacid generator is used for the ultraviolet curable resin. The addition amount of (curing agent) is increased or a sensitizer is used in combination. However, since the photoacid generator and the sensitizer are compounds having a chromophore, as the added amount thereof increases, the transparency of the manufactured optical component decreases. Since optical components such as optical lenses are components that allow light to pass through, a decrease in transparency is a problem that should be avoided. Therefore, if the addition amount of the photoacid generator or the like is decreased in order to avoid a decrease in transparency, the curability is deteriorated and the production efficiency is lowered.

  Further, from the viewpoint of recent environmental load reduction, it is desirable to use an LED (light emitting diode) with low power consumption instead of a generally used mercury lamp as the ultraviolet light source. However, an LED generally used industrially has a single emission wavelength in the 355 to 375 nm region, and unlike the mercury lamp, does not emit high-energy short-wavelength ultraviolet rays. For this reason, it takes time to cure the ultraviolet curable resin (the curability is poor), resulting in a problem that the productivity is lowered. Therefore, when the amount of photoacid generator and sensitizer added to the ultraviolet curable resin is increased so that the curability of the ultraviolet curable resin does not deteriorate even when the LED is used, this time, as described above, The transparency of manufactured optical components is greatly reduced.

The present invention is such made in view of the circumstances, an excellent highly transparent in production efficiency steric optical lens or an optical waveguide or an optical lens or an optical waveguide or an optical fiber it is possible to obtain a core of the optical fiber It is an object of the present invention to provide a method for manufacturing the core .

In order to achieve the above object, an optical lens or optical waveguide or optical fiber core manufacturing method of the present invention supplies an ultraviolet curable resin containing an epoxy resin as a main component and a photoacid generator on a substrate. The ultraviolet curable resin is embossed with a molding die, and the ultraviolet curable resin thus exposed is irradiated with ultraviolet rays to expose the ultraviolet curable resin. A method for producing a three-dimensional optical component comprising a cured body, wherein the photoacid generator in the ultraviolet curable resin is in the range of 0.1 to 4% by weight, and the exposure with the ultraviolet rays is performed as described above. The ultraviolet curable resin is heated within a range of 40 to 60 ° C. , and the gelation time is 69 to 315 seconds .

Note that you Keru the present invention "optical lens or an optical waveguide or core of an optical fiber" is Ru optics der that spend translucent light. Hereinafter, the “optical lens or optical waveguide or optical fiber core” is simply referred to as “optical component”.

The inventors of the present invention use an ultraviolet curable resin containing an epoxy resin as a main component and a photoacid generator as a material, and increase production efficiency when manufacturing a three-dimensional optical component by embossing a molding die. In order to improve the transparency of parts, research was repeated on the exposure process using ultraviolet rays. In the course of that research, we found out that when UV curable resin is exposed in a heated state, curing of UV curable resin is accelerated even if the amount of photoacid generator added to the UV curable resin is reduced. It was. That is, by doing in this way, since the addition amount of a photo-acid generator etc. which causes the transparency fall of an optical component can be decreased, the transparency of an optical component can be improved. Moreover, since the curing of the ultraviolet curable resin is accelerated, the production efficiency of the optical component can be increased. As a result of further research on the heating temperature at the time of the exposure, it was found that when the heating temperature is in the range of 30 to 60 ° C., the ultraviolet curable resin is properly cured. That is, when the temperature of the ultraviolet curable resin at the time of exposure is less than 30 ° C., the curability of the ultraviolet curable resin is deteriorated and the production efficiency is lowered. It becomes large and dimensional stability deteriorates. In particular, when the heating temperature is in the range of 40 to 60 ° C., the gelation time can be shortened to 69 to 315 seconds.

The method for producing an optical component according to the present invention uses an ultraviolet curable resin containing an epoxy resin as a main component and containing a photoacid generator as a material. When producing a three-dimensional optical component by pressing a molding die, exposure by ultraviolet rays is performed. but warmed in the range of 4 0 to 60 ° C. the ultraviolet curable resin is performed in a state in which the gel time to 69-315 seconds. For this reason, even if the addition amount of a photo-acid generator etc. to ultraviolet curable resin is decreased, hardening of ultraviolet curable resin can be accelerated. That is, the transparency of the optical component can be increased and the production efficiency can be increased. Furthermore, since the upper limit of the temperature of the ultraviolet curable resin at the time of exposure is 60 ° C., the thermal shrinkage of the optical component is small and the dimensional stability is excellent.

In addition, heating the ultraviolet curable resin within a range of 40 to 60 ° C. heats at least one of the substrate and the mold prior to supplying the ultraviolet curable resin onto the substrate. In the case where it is carried out, the temperature of the substrate and the mold can be adjusted in consideration of the product temperature of the supplied UV curable resin, etc., so that the temperature control can be precisely performed, and the above UV curable Easier heating of the resin can be realized.

In particular, when the ultraviolet light source is an LED having a single emission wavelength, the burden on the environment can be reduced compared to the case where a mercury lamp is used as the light source. In this case, as described above, an LED generally used industrially does not emit high-energy short-wavelength ultraviolet light unlike a mercury lamp. The curability of the curable resin is poor and the production efficiency is lowered. Therefore, if the amount of photoacid generator added to the UV curable resin is increased so that the curability of the UV curable resin is not deteriorated even if an LED is used, this time, the transparency of the manufactured optical component is greatly increased. To drop. On the other hand, in the present invention, since the curability is improved by heating the temperature of the ultraviolet curable resin at the time of exposure within the range of 40 to 60 ° C., the ultraviolet light source is an LED. However, production efficiency can be increased. In addition, the above-described improvement in curability can reduce the amount of photoacid generator and the like added to the ultraviolet curable resin even if the ultraviolet light source is an LED, thereby increasing the transparency of the optical component. it can. Furthermore, since the power consumption of the LED is small, as described above, the load on the environment can be reduced and the recent environmental problems can be dealt with.

Moreover, since the said ultraviolet curable resin is what has an epoxy resin as a main component, since an epoxy resin is excellent in heat resistance and heat shrink is small, it is excellent in the dimensional stability of an optical component.

It is sectional drawing which shows typically the optical component obtained by one Embodiment of the manufacturing method of the optical component of this invention. (A)-(e) is explanatory drawing which shows typically one Embodiment of the manufacturing method of the optical component of this invention. It is explanatory drawing which shows typically the modification which presses an ultraviolet curable resin with a shaping | molding die. It is a graph which shows the emission spectrum of the mercury lamp used for Example 1 , 2, Reference example 1, and Comparative Examples 1-3.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing an optical component obtained by an embodiment of a method for manufacturing an optical component of the present invention. The optical component A1 is made of an ultraviolet curable resin, and a plurality (seven in FIG. 1) are formed on the substrate 1. Examples of the shape of the optical component A1 include a three-dimensional shape such as a lens shape, a cubic shape, a rectangular parallelepiped shape, a prismatic shape, a cylindrical shape, a spherical shape, a spherical shape, a curved surface shape, a pyramid shape, and a conical shape (FIG. 1). In the figure of a cube).

  Such a three-dimensional optical component can be manufactured as follows.

  First, as shown in FIG. 2A, an ultraviolet curable resin (not shown), which is a material for forming the optical component A1, a substrate 1 to which the ultraviolet curable resin is supplied, and the substrate 1 A mold 2 for embossing an ultraviolet curable resin is prepared. On the mold surface of the mold 2, a recess 2 a is formed by pressing the ultraviolet curable resin into a desired three-dimensional shape. Note that at least one of the substrate 1 and the mold 2 is made of a material that transmits ultraviolet rays.

  The ultraviolet curable resin is composed of a resin component such as an epoxy resin and an additive such as a photoacid generator (curing agent), and the addition of the additive is higher than the conventionally used ultraviolet curable resin. The amount is decreasing. In the conventionally used ultraviolet curable resin, the photoacid generator in the ultraviolet curable resin is in the range of 5 to 8% by weight (hereinafter abbreviated as “%”). It is in the range of 1 to 4%. Thus, even if the addition amount of the photoacid generator is small, in the present invention, the curing of the ultraviolet curable resin can be accelerated. Examples of the resin component of the ultraviolet curable resin include acrylic resin, acrylic urethane resin, and silicone resin in addition to the epoxy resin. These may be used alone or in combination of two or more. Among these, an epoxy resin is preferable from the viewpoint of excellent heat resistance and heat shrinkability. Moreover, as said additive, in addition to the said photo-acid generator, you may use a sensitizer etc. together as needed.

  Examples of the material for forming the substrate 1 include glass and resin. Examples of the glass include white plate glass, quartz glass, Pyrex (registered trademark) glass, BK-7, and blue plate glass. Examples of the resin include polyolefin, thermosetting resin, and photocurable resin. Among them, examples of the polyolefin include polyethylene, polypropylene, polystyrene, polymethyl methacrylate, and polyethylene terephthalate. As said thermosetting resin and photocurable resin, an epoxy resin, a polyimide resin, an acrylic resin, a silicone resin etc. are mention | raise | lifted, for example. These may be used alone or in combination of two or more. Of these, white plate glass is preferable from the viewpoints of versatility, transparency, and heat resistance.

  The molding die 2 has a recess 2a corresponding to the shape of the optical component A1 on the lower surface (mold surface). Examples of the forming material of the mold 2 include metal, glass, and resin. Examples of the mold made of the metal include those having a nickel plating layer, a chromium plating layer, or the like formed on the surface. From the viewpoint of transparency, glass, resin and the like are preferable. Examples of the glass include white plate glass, quartz glass, Pyrex (registered trademark) glass, BK-7, and blue plate glass. Examples of the resin include polyolefin, thermosetting resin, and photocurable resin. Among them, examples of the polyolefin include polyethylene, polypropylene, polystyrene, polymethyl methacrylate, and polyethylene terephthalate. As said thermosetting resin and photocurable resin, an epoxy resin, a polyimide resin, an acrylic resin, a silicone resin etc. are mention | raise | lifted, for example. These may be used alone or in combination of two or more. Among these, from the viewpoints of versatility, light resistance, and mold releasability, a mold having a nickel plating layer and a silicone resin mold are preferable. From the viewpoint of releasability, a mold release agent such as fluorine or silicone may be applied to the mold surface 2 a of the mold 2.

Next, after preparing the ultraviolet curable resin, the substrate 1 and the mold 2 as described above, add at least one (one or both) of the substrate 1 and the mold 2 within the range of 40 to 60 ° C. Warm up. As the heating method, for example, a method of placing the substrate 1 and the mold 2 on a hot plate, a method of radiating a heat source such as a heating wire or a ceramic heater to the substrate 1 and the mold 2, For example, a method of blowing hot air on the substrate 1 and the mold 2 can be used.

  Next, as shown in FIG. 2B, the ultraviolet curable resin (liquid or pasty) A is potted (supplied) on the substrate 1 using a potting device or the like. The ultraviolet curable resin A potted on the substrate 1 becomes a dome-shaped layer due to its own surface tension.

  Next, as shown in FIG. 2 (c), the mold 2 is pressed (pressed) against the substrate 1 with the mold surface 2 a of the mold 2 facing the surface of the substrate 1. In this embodiment, the mold surface of the mold 2 is brought into close contact with the surface of the substrate 1. As a result, the ultraviolet curable resin A on the substrate 1 enters and fills in the concave portion 2 a of the mold surface of the mold 2, and the dome-shaped layer of the ultraviolet curable resin A has the shape of the concave portion 2 a of the mold 2. To be molded.

Thus, in the state where the ultraviolet curable resin A is embossed with the mold 2, by heating in the range of 40 to 60 ° C. with respect to at least one of the substrate 1 and the mold 2 in the first step, The heat is conducted to the embossed ultraviolet curable resin A, and the ultraviolet curable resin A is also heated within a range of 40 to 60 ° C. The heating temperature of the ultraviolet curable resin A is more preferably in the range of 35 to 55 ° C. from the viewpoint of heat shrinkage and curability. In addition, the measurement (confirmation) of the heating temperature of the said ultraviolet curable resin A can be performed with a thermocouple, for example.

Then, in the heated state of the ultraviolet curable resin A, as shown in FIG. 2 (d), at least one of the substrate 1 and the mold 2 is transmitted and irradiated with the ultraviolet light L, thereby the ultraviolet curable resin. A is exposed, the ultraviolet curable resin A is cured, and a three-dimensional optical component A1 is formed. Examples of the light source of the ultraviolet light L include a mercury lamp, an LED having a single wavelength within a 355 to 375 nm emission wavelength, and the like. Among these, a mercury lamp is preferable from the viewpoint of emitting high-energy short-wavelength ultraviolet light L, and an LED is preferable from the viewpoint of reducing power consumption and reducing the burden on the environment. Thus, it is a major feature of the present invention that the ultraviolet curable resin A is exposed to the ultraviolet light L in a state where the ultraviolet curable resin A is heated within a range of 40 to 60 ° C.

  Then, as shown in FIG. 2E, the three-dimensional optical component A1 such as an optical lens is obtained by removing the demolded and cured photosensitive resin from the substrate 1.

In the above embodiment, at least one of the substrate 1 and the molding die 2 is heated prior to potting the ultraviolet curable resin A on the substrate 1, but the ultraviolet curable resin A is molded with the molding die 2. In the pressed state, at least one of the substrate 1 and the mold 2 is heated, and the temperature of the ultraviolet curable resin A at the time of ultraviolet irradiation is within a range of 40 to 60 ° C. (more preferably 35 to 55 ° C.). May be warm.

  In the above embodiment, after removing the mold in the step shown in FIG. 2E, the cured photosensitive resin is peeled from the substrate 1 to obtain the optical component A1, but the cured photosensitive resin is attached. The obtained substrate 1 may be obtained as an optical component as it is.

  Further, in the above embodiment, when the ultraviolet curable resin A is embossed with the mold 2 as shown in FIG. 2C, the lower surface of the mold 2 is brought into close contact with the surface of the substrate 1. As shown in FIG. 3, the mold 2 is pressed so that the lower surface of the mold 2 does not adhere to the surface of the substrate 1, and the mold surface 2a of the mold 2 is placed on the surface portion of the layer of the ultraviolet curable resin A. A three-dimensional optical component in which convex portions are formed on the surface of the flat plate-like body may be manufactured by curing in a state where the shape of the plate is transferred.

Next, examples and reference examples will be described together with comparative examples. However, the present invention is not limited to the examples.

[Examples 1 to 4 and Reference Examples 1 and 2 , Comparative Examples 2 to 4]
[Ultraviolet curable resin (A): type with a small amount of hardener added]
50 g of bisphenol A type epoxy resin (Japan Epoxy Resin, Epicoat 827), 50 g of alicyclic epoxy resin (CEL-2021P, manufactured by Daicel Chemical Industries), 1 g of curing agent (Adeka Corp., Adeka Optomer SP-170) The ultraviolet curable resin (A) was prepared by stirring and mixing at 50 ° C. for 10 minutes, and then allowed to stand until it fell below 25 ° C. The ultraviolet curable resin (A) had a viscosity of 1540 mPa · s at 25 ° C., and the cured product had a thermal expansion coefficient of 88 ppm / K.

[Relatively 1]
[Ultraviolet curable resin (B): type with a large amount of curing agent added]
In the ultraviolet curable resin (A), the amount of the curing agent added was 4 g, and the ultraviolet curable resin (B) was used. Other than that was carried out similarly to the said ultraviolet curable resin (A). The ultraviolet curable resin (B) had a viscosity at 25 ° C. of 1440 mPa · s, and the cured product had a thermal expansion coefficient of 88 ppm / K.

  Using the ultraviolet curable resins (A) and (B), each characteristic was evaluated according to the following criteria. The results are shown in Tables 1 and 2 below.

[Gelging time of UV curable resins (A) and (B)]
Tables 1 and 2 below show the viscoelasticity of the UV curable resins (A) and (B) during UV irradiation using a Rheologyka UV rheometer (a 15 mm diameter aluminum plate is used as a rotating plate). The time from the start of measurement to the intersection of the elastic term and the viscosity term was defined as the gelation time. And the thing whose gelation time is 700 seconds or less was evaluated as ○, and the thing exceeding it was evaluated as ×.

As the ultraviolet light source, as shown in Tables 1 and 2 below, a mercury lamp (manufactured by Hamamatsu Photonics Co., Ltd., LC-8: see FIG. 4 for the emission spectrum, illuminance of 10 mW / cm ² at a wavelength of 365 nm) or UV-LED (manufactured by Hamamatsu Photonics, light source type L9613-200: wavelength 365 nm single wavelength, illuminance 10 mW / cm ² ) was used. The temperature of the ultraviolet curable resins (A) and (B) at the time of measuring the viscoelasticity is a temperature heated by hot air from a dryer, and can be measured (confirmed) by a thermocouple.

[Coloring degree of ultraviolet curable resins (A) and (B)]
A molding die (diameter 50 mm × thickness 268 μm) using a thermosetting resin (SYLGARD 184, manufactured by Dow Corning) was produced. Then, after potting the ultraviolet curable resins (A) and (B) on a Pyrex (registered trademark) glass substrate, the molds are embossed with the molds, and the temperatures shown in Tables 1 and 2 below are set. Then, a molded product was produced by irradiating ultraviolet rays from each light source. Next, after heating and curing at 100 ° C. for 1 hour, the yellow index was measured using a color computer (SM-T, manufactured by Suga Test Instruments Co., Ltd.). The yellow index of 5 or less was evaluated as ○, and the index exceeding it was evaluated as ×.

[Dimensional error (shrinkage rate) of molded product]
A molding die (diameter 50 mm × thickness 224 μm) made of a thermosetting resin (SYLARD184, manufactured by Dow Corning) was produced. Then, after potting the ultraviolet curable resins (A) and (B) on a Pyrex (registered trademark) glass substrate, the molds are embossed with the molds, and the temperatures shown in Tables 1 and 2 below are set. Then, a molded product was produced by irradiating ultraviolet rays from each light source. Thereafter, the cavity depth of the mold and the height of the molded product were measured using a stylus type surface shape measuring instrument (Dektak 8 manufactured by ULVAC, Inc.), and the shrinkage ratio of the molded product with respect to the mold was calculated. And the thing with the shrinkage | contraction rate of 2.00% or less was evaluated as (circle) and what exceeded it x.

From the above results, in Examples 1 to 4 and Reference Examples 1 and 2 , it was possible to obtain molded articles having a short gelation time, a low degree of coloring, and a small shrinkage rate. In particular, in Examples 1 to 4, the gelation time was short. On the other hand, in Comparative Example 1, although the gelation time and the shrinkage rate were good, a remarkably colored molded product was obtained. This is because the amount of the curing agent added in the ultraviolet curable resin (B) is large. In Comparative Example 2, although the degree of coloring and the shrinkage rate were good, the gelation time was long. This is because, despite the use of a mercury lamp as the light source, the amount of the curing agent added to the ultraviolet curable resin (A) is small, and the heated temperature is low. In Comparative Example 3, a molded article having a high shrinkage rate was obtained although the gelation time and the coloring degree were good. This is because the heated temperature is high. In Comparative Example 4, although the degree of coloring and the shrinkage rate were good, the gelation time was long. This is because the amount of the curing agent added to the ultraviolet curable resin (A) is small and the heated temperature is low.

  In addition, although the said ultraviolet curable resin (A) and (B) shall have an epoxy resin as a main component, even if it uses what has an acrylic resin, an acrylic urethane resin, and a silicone resin as a main component, the said Similar results were obtained.

Method of manufacturing an optical component of the present invention is applicable to the manufacture of core of the optical lens, an optical waveguide or an optical fiber.

1 Substrate 2 Mold A UV curable resin A1 Optical component L UV

Claims (3)

On the substrate, an ultraviolet curable resin containing an epoxy resin as a main component and containing a photoacid generator is supplied, and the ultraviolet curable resin is embossed with a molding die. A method for producing a three-dimensional optical component comprising a cured product of the ultraviolet curable resin by exposing the ultraviolet curable resin to ultraviolet rays on the resin, wherein the photoacid in the ultraviolet curable resin is produced. The generator is within the range of 0.1 to 4% by weight, and the exposure with the ultraviolet rays warms the ultraviolet curable resin within the range of 40 to 60 ° C. , and the gelation time is 69 to 315 seconds. An optical lens or a method of manufacturing a core of an optical waveguide or an optical fiber, which is performed in the state described above. Heating the ultraviolet curable resin within a range of 40 to 60 ° C. heats at least one of the substrate and the mold prior to supplying the ultraviolet curable resin onto the substrate. The manufacturing method of the core of the optical lens of Claim 1, or an optical waveguide, or an optical fiber performed by these . 3. The method of manufacturing an optical lens, an optical waveguide, or an optical fiber core according to claim 1, wherein the ultraviolet light source is an LED having a single emission wavelength.

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